Preheat oven to 325F (163C).
Combine the donut ingredients (not including the coating), and mix well.
Spoon into a ziplock bag, and cut off the corner to pipe these into your donut pan (or you can just spoon the batter into the pan).
Bake for 14-16 minutes if using a dark, non-stick pan. Add a few minutes if using silicone pan.
Remove from oven, and let cool. Then remove from pan.
Mix erythritol and cinnamon in a bowl.
Brush each donut with melted coconut oil (to make the coating stick), and dip into the coating.
Enjoy! Donuts can stay out for the day, but refrigerate for longer storage.